fix(nvim): stop treesitter parser drift from local site installs

Force nvim-treesitter to avoid startup parser installs and rely on Nix-provided grammars only, preventing stale ~/.local/share/nvim/site/parser .so files from causing query/parser mismatches (e.g. vim "tab" node errors on ":").

modules/editor/vim/lua/plugins/treesitter.lua

@@ -1,11 +1,10 @@
 return {
   {
     "nvim-treesitter/nvim-treesitter",
-    opts = {
-      auto_install = false,
-      sync_install = false,
-      ensure_installed = {},
-      parser_install_dir = vim.fs.joinpath(vim.fn.stdpath('data'), 'site'),
-    },
+    opts = function(_, opts)
+      opts.auto_install = false
+      opts.sync_install = false
+      opts.ensure_installed = {}
+    end,
   },
 }